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How Many Drinks Does it Take to Reach 0.08% BAC?

In an era of heightened awareness about the perils of drinking and driving, the decimal 0.08 requires no explanation.

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When your blood alcohol content (BAC) is 0.08% or higher, you’re considered legally impaired in the U.S.

While you are certain to be arrested for suspicion of driving under the influence (DUI) when your BAC is at or over 0.08%, you can still be charged if your BAC is at any level above 0.00%.

If a police officer deems you “noticeably impaired”, or if you fall under your state’s zero tolerance laws (e.g., you're under 21 or have children in the car), you could face a DUI even if you are under the legal limit.

When Does My “BAC Clock” Start?

When you use an accurate and convenient BACtrack Professional Grade Breathalyzer, you can measure your BAC just 15 minutes after you consume your first drink. According to conventional wisdom, your BAC level will remain within safe limits if you consume only one standard drink per hour. As defined by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), a standard drink is half an ounce of alcohol. That means one 12-ounce beer, one five-ounce glass of wine, and one 1.5-ounce shot of distilled spirits each count as one standard drink.

We all know that conventional wisdom can be wrong, though, and sometimes wildly so. Intoxication begins with the very first drink. You should never drink and drive, no matter how much you’ve consumed. You can be impaired and arrested even if your BAC is under 0.08%.

Unlike charts, calculators, or rules, BACtrack Breathalyzers don’t use generalizations–they use your breath to estimate your BAC. No other method is quite so fast, convenient and reliable.

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Common Factors That Affect BAC

Seeing as there are many factors affecting BAC, it’s very difficult to estimate how many drinks it would take for an “average person” to reach 0.08%. Additionally, not all drinks are created the same — a cocktail served at one bar may have double the alcohol as that served at another bar. If you keep a BACtrack Mobile Pro Breathalyzer on hand, you’ll know right away just how your BAC adds up, no matter which of these factors affect you.

Some common factors include:

  • Age
  • Gender
  • Rate of consumption
  • Drink strength
  • Body type
  • Fat/Muscle content
  • Metabolism
  • Hydration
  • Emotional state
  • Medications you are on
  • Food you’ve consumed
  • Carbonation of drinks
  • Alcohol tolerance
  • Overall health

A Real World BAC Example

To show just how dramatically BAC can be affected by these factors, let’s take a look an example. Bill, Suzie, and Raymond all went out for pizza and drinks last Saturday night. Over the course of 90 minutes, each of them consumed the same exact thing: 2 slices of pizza, 1 pint of beer (containing 4.2% alcohol), and 2 glasses of Pinot Noir (13% alcohol). Bill weighs 215 lbs, Raymond weighs 175lbs, and Suzie weighs 150 lbs.

At the end of the night, they finished their glasses of wine and waited 15 minutes. Then they used a Professional Grade BACtrack to test themselves. Here’s what they found.







Needless to say, they all decided to take cabs home. But it’s important to realize that BAC can vary widely depending on a host of factors. The results would certainly have been different if they hadn’t eaten, or if their rate of alcohol consumption was different. That’s why being able to accurately test your alcohol level is critical to your safety and that of those around you.

You should never drink and drive, no matter how much you’ve consumed. You can be impaired and arrested even if your BAC is under 0.08%.

The Difference Between DUI and DWI

While both DUI and DWI refer to the act of driving while under the influence of drugs or alcohol, they can be separate, though related crimes depending on where you are driving and your age.

If you live in a locale that classifies them discretely, the charge usually depends on the driver’s BAC level at the time of the arrest–DUI is the lesser change, DWI the more serious.

For example, in Texas, if you have alcohol in your system, and especially if you have a BAC of 0.08% or above, you are arrested for DWI. You would only get a DUI if you were under 21 with any amount of alcohol in your system. In New York State, if you have a BAC of 0.08% or above, you would be charged with a DWI, while you would be arrested for DUI if your BAC was below 0.08%. Some states don’t make the distinction at all. In Illinois, for example, there is no DWI—only DUI.

Calculating Your BAC


As you imbibe alcoholic beverages and approach the 0.08% BAC legal driving limit, you may notice that you’re less inhibited and more extroverted than normal. If you continue drinking and sail past 0.08% BAC, you may experience dramatic mood swings, slurred speech, and, worst of all, unsound judgment. The obvious call: Don’t get in your car and drive. That decision isn’t so easy when you aren’t thinking clearly. Self-assessment is a poor method of calculating your BAC.

One-Drink-Per-Hour Rule

In the beginning, the one-drink-per-hour rule doesn’t seem hard to track. Plus, it’s convenient and free. Not all drinks are created equal, though. Wine and beer have varying alcohol concentrations, and the strength of a mixed drink can fluctuate significantly depending on who mixes it. Add inebriated judgment to the mix, and you have a recipe for ruin. The one-drink-per-hour rule is too easy to break to be of any use in calculating an accurate BAC.

BAC Calculators and Charts

Free and readily available online, BAC calculators and charts claim to help you approximate your BAC levels based on your gender, weight, and quantity of drinks consumed. If this sounds simple, think again. BAC calculators and charts make huge assumptions about the strength of your drinks, and they don’t take into account personal factors such as your metabolism, health, medications, and recent consumption of food. When it comes to calculating BAC, these tools aren’t personalized enough to be of use.

Breath Testing

Commercially available breath testing units are the most reliable way to measure your BAC. BACtrack’s Professional Grade Breathalyzers are the most accurate, lightweight, portable, and reliable instruments on the market.

BACtrack Professional Grade Breathalyzers use Xtend® Fuel Cell Sensors, the same technology law enforcement officers use for roadside testing. Unlike charts, calculators, or rules, these devices don’t use generalizations–they are totally personal to you; using your breath to estimate your BAC. No other method is quite so fast, convenient and reliable.